Improvement in hot-air engines



S. H. ROPER. AIR ENGINE.

No. 34,728. Patented Mar. 18, 1862.

jnwnf-r $5 3732 UNITED STATES PATENT OFF CE.

S. H. ROPER, OF ROXBURY, ASSIGNOR TO ELMER TOWNSEND, OF BOSTON,

' MASSACHUSETTS.

IMPROVEMENT IN HOT-AIR ENGINE S.

Specification forming part of Letters Patent No. 34,723, dated Match 18, 1862.

To all whom it may concern.-

Be it known. that I, S. H. ROPER, of Rox-Y bury, in the county of Norfolk and State of Massachusetts, have invented certain Improvements in I-I ot-A-ir Engines, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, making 'part of this specification, in which Figure 1 is a vertical section through the fire-box, working-cylinder, andmy improwed arrangement of valves and valve-chest (if a hot-air engine. Fig. 2 is a view of the valvechest.

In the hot-air engines in which the air for operating the piston is forced through the furnace or fire-box and is admitted to the working-cylinder through valves, as in the engine for which I made application for patent June 22, 1861, a difficulty occurs in having the valves placed in such a position that they are exposed to the direct radiation from the fire, which effects their corrosion and destruction much sooner than if the hot air only came into contact with them. To remedy this is the object of my present invention,

which consists in attaching to the outside of the shell or case of the hot-air engine a valvechest in which the valves and their communicating chambers and passages foradmitting the hot air to and from the working-cylinder are placed and 'work, by which the valves are --not only protectedfrom the direct radiation {of the fire, but are in such a position -Jthat they are easily accessible for adjustment or "repairs.

That others skilled in the art may underi stand and use my invention, I will proceed to or partition which separates this cylinder from the furnace, and in which the valves have heretofore been placed.

F is a valve-chest, which is attached to the shell A on one side, an opening a being made through the side of the shell A into the lower partition I), and another opening a into the upper partition d of the valve-chest. It will be seen by reference to Fig. 1 that this valvechest is divided into three portions, 1),.(1, and e, by suitable partitions, the latter division e opening at f to the atmosphere.

A valve G commands an opening h from the division I; to the division (1, and another valve II commands an opening on from, the division (Z to the division (sand the outer atmosphere. These valves are operated by an ordinary rock-shaft 70, Fig. 2, and are closed by springs Z on their stems.

The operation is as follows: The air being forced into the furnace and there heated and expandedis admitted by the opening of the valve G to the cylinder I), and the piston I is raised. This valve is now closed and the valve H'is opened to permit the cylinder D to exhaust through the opening f into the atmosphere. A cap n'on top of the valve-chest F gives access to the valve II, and another similar cap 1.) onthe bottom of the chest gives access to the valve G.

What I-claim as my invention, and desire to secure by Letters Patent, as an improvementin hot-air engines in which the workingcylinder is separated by a partition or diaphragm from the furnace or fire-box, is-- The arrangement of the valves and their communicating chambers and passages within a valve-chest F on the outsideo'f'the shell or casing A, substantially as and for the purpose set. forth.

s. H. ROPER. Witnesses:

THOS. B. Home, A EDMUND MASSON. 

